1. Field of the Invention
The invention is related to the field of optical communications, and in particular, to communication systems the provide hybrid ring/mesh protection.
2. Description of the Prior Art
Communication nodes may exchange communications with one another over a work path in an optical ring. If the work path in the optical ring experiences a fault, the nodes may transfer the affected communications over a protect path in the opposite direction around the optical ring. The protect path must have the same capacity as the work path. Unfortunately, the protect path may be much longer than the work path and costly to implement.
Line protection may be used as an alternative to path protection in the optical ring. A work path is typically comprised of a series of work lines that are coupled together to form the work path. These work lines can have corresponding protect lines that are physically or geographically diverse from the work lines. If a work line in the optical ring experiences a fault, the nodes may transfer the affected communications over a corresponding protect line—possibly in the opposite direction around the optical ring. The protect line must have the same capacity as the work line. Unfortunately, the protect line may be much longer than the work line and costly to implement.
Both path protection and line protection in an optical ring are referred to below as ring protection.
Communication nodes may also exchange communications with one another over links in an optical mesh. If a link in the optical mesh experiences a fault, the nodes re-route the affected communications through the optical mesh around the fault. Unfortunately, the mesh protection may be slower than ring protection.
Ring protection and mesh protection have not been effectively integrated into a hybrid protection system.